The field of the invention relates generally to power generation systems and, more particularly, to systems and methods for reconditioning turbine engines in power generation systems by coolant flow direction reversals.
At least some known turbine engines are used in power generation systems, such as cogeneration facilities and power plants. Such engines may have high specific work and power per unit mass flow requirements. To increase their operating efficiency, at least some known turbine engines, such as gas turbine engines, operate with increased combustion temperatures. In at least some known gas turbine engines, engine efficiency may increase as combustion gas temperatures increase.
Due to the increase in the combustion gas temperatures, at least some known gas turbine engines use relatively small cooling holes or passages to deliver cooling air to critical areas within the turbine engine. However, dust particles that may be ingested through an inlet of the turbine engine as well as other deposits and debris may become trapped within the cooling holes or passages and substantially limit the flow of cooling fluid there through. Similarly, small metal fragments detach from the engine may also become trapped within the cooling holes or passages. When the cooling holes or passages become blocked, the operating temperature of those components may increase and this temperature increase may cause damage to the components and/or may lead to a premature failure of the components and/or the turbine engine.
To prevent such blockage from occurring, at least some known gas turbine engines use relatively larger holes or passages. However, over time, dust particles and small metal fragments may still accumulate and cause blockages within the larger holes or passages. As a result, at least some known gas turbine engines use a cleaner air supply therein such that the internal cooling holes or passages may be free of deposits. More specifically, at least some known gas turbine engines may be cleaned or reconditioned with a mixture that includes water, steam, and/or air. The mixture is injected at the inlet of the gas turbine engine in an attempt to remove deposits that are formed on, for example, the gas-path surface of the airfoils. However, it may be difficult to channel the mixture to inside the cooling passages that are formed in the airfoil. As a result, blockages within the cooling holes or passages may still form.